BSA Calculator (Mosteller Formula) – Calculate Body Surface Area
Use this calculator to determine Body Surface Area (BSA) using the Mosteller formula based on height and weight. This is a common method to calculate BSA using Mosteller formula.
Enter your height.
Enter your weight.
Your Body Surface Area (BSA)
Height: 0 cm
Weight: 0 kg
Height x Weight: 0
BSA vs. Weight (for current height)
| Category | Typical BSA (m²) |
|---|---|
| Average Adult Man | 1.9 |
| Average Adult Woman | 1.6 |
| 10-year-old Child | ~1.14 |
| 1-year-old Child | ~0.5 |
| Newborn | ~0.25 |
Typical Body Surface Area values for different categories.
What is Body Surface Area (BSA) and the Mosteller Formula?
Body Surface Area (BSA) is the measured or calculated surface area of a human body. It is often used in medicine, particularly for determining dosages of certain medications, especially chemotherapy drugs, and for assessing the extent of burns. While several formulas exist to estimate BSA, the Mosteller formula is widely used due to its simplicity and reasonable accuracy for a range of body sizes. To calculate BSA using Mosteller formula, you only need the individual’s height and weight.
The Mosteller formula was proposed in 1987 and is valued for being easy to remember and apply. It’s used by doctors, pharmacists, and researchers to estimate BSA when direct measurement isn’t practical. Common misconceptions include thinking BSA is the same as BMI (Body Mass Index) – they are different measures, with BMI relating weight to height squared, while BSA relates to the total surface area.
Mosteller Formula and Mathematical Explanation
The Mosteller formula to calculate BSA using Mosteller formula is expressed as:
BSA (m²) = √((Height (cm) × Weight (kg)) / 3600)
Where:
- BSA is the Body Surface Area in square meters (m²).
- Height is the person’s height in centimeters (cm).
- Weight is the person’s weight in kilograms (kg).
The formula involves multiplying the height in cm by the weight in kg, dividing the product by 3600, and then taking the square root of the result.
| Variable | Meaning | Unit | Typical Range (Adult) |
|---|---|---|---|
| Height | Person’s height | cm | 150 – 200 cm |
| Weight | Person’s weight | kg | 50 – 100 kg |
| BSA | Body Surface Area | m² | 1.5 – 2.2 m² |
Variables used in the Mosteller formula to calculate BSA.
Practical Examples (Real-World Use Cases)
Example 1: Average Adult Male
Let’s consider an adult male with a height of 178 cm (approx 5 ft 10 in) and a weight of 75 kg (approx 165 lbs).
BSA = √((178 × 75) / 3600) = √(13350 / 3600) = √3.7083 ≈ 1.93 m²
This BSA value might be used to calculate the appropriate dose of a medication for this individual.
Example 2: Child
Consider a child with a height of 120 cm and a weight of 25 kg.
BSA = √((120 × 25) / 3600) = √(3000 / 3600) = √0.8333 ≈ 0.91 m²
For children, BSA is particularly important for accurate dosing of many drugs, as their metabolism and drug distribution differ from adults.
How to Use This BSA Calculator (Mosteller Formula)
Using this calculator to calculate BSA using Mosteller formula is straightforward:
- Enter Height: Input the person’s height. You can select the unit (cm or ft & in). If using ft & in, enter the feet in the first box and inches in the second box that appears.
- Enter Weight: Input the person’s weight. Select the unit (kg or lbs).
- View Results: The calculator will automatically update and display the calculated BSA in square meters (m²), along with the height and weight used in the calculation (converted to cm and kg if needed). The chart and intermediate values will also update.
- Interpret Results: The primary result is the BSA. You can compare this to typical values or use it as directed by a healthcare professional for drug dosage BSA calculations.
Key Factors That Affect BSA Results
- Height: BSA increases with height. Taller individuals have a larger surface area.
- Weight: BSA increases with weight. Heavier individuals generally have a larger surface area.
- Age and Gender: While the Mosteller formula itself doesn’t directly use age or gender, these factors influence average height and weight, thus indirectly affecting typical BSA values. See our ideal weight calculator for more context.
- Body Composition: The formula assumes a relatively standard body shape. Individuals with very unusual body compositions (e.g., extremely muscular or very high body fat) might have a BSA slightly different from the estimate. Our body fat calculator might be relevant.
- Hydration Status: Significant changes in hydration can alter weight, thus slightly affecting the calculated BSA.
- Formula Choice: Other formulas (like Du Bois, Haycock, Gehan & George) exist and may give slightly different results, especially for very young or obese individuals. The Mosteller formula is a good general-purpose choice.
Frequently Asked Questions (FAQ)
BSA is the total surface area of the human body. It’s a physiological parameter used in medicine, particularly for dosing medications and assessing burns.
BSA is often more closely related to metabolic rate, cardiac output, and drug distribution than body weight alone, especially for certain medications like chemotherapy agents. Using BSA helps in more accurate dosing. It’s a key part of drug dosage BSA calculations.
The Mosteller formula provides a good estimate for most adults and children. However, for individuals at the extremes of body size or shape, other formulas might be more accurate. Always consult a healthcare professional for medical decisions based on BSA.
Our calculator allows you to enter height in centimeters (cm) or feet & inches (ft & in), and weight in kilograms (kg) or pounds (lbs). The formula internally uses cm and kg, and the calculator handles the conversions for you.
It’s used to calculate doses for chemotherapy, some antibiotics, and other drugs. It’s also used to estimate fluid requirements in burn patients and assess kidney function (glomerular filtration rate).
Yes, other common formulas include the Du Bois and Du Bois formula, the Haycock formula, and the Gehan and George formula. Each has slight variations and may be preferred in specific populations.
Yes, the Mosteller formula is generally considered acceptable for use in children, although some pediatric-specific formulas also exist.
The Mosteller formula is generally robust, but at extremes of weight, the accuracy might be slightly reduced compared to more complex methods or other formulas. You might also want to check our BMI calculator.
Related Tools and Internal Resources
- BMI Calculator: Calculate your Body Mass Index to assess weight status.
- Ideal Weight Calculator: Find your ideal weight based on different formulas.
- Calorie Calculator: Estimate your daily calorie needs.
- Drug Dosage BSA Information: Learn more about how BSA is used for drug dosing.
- Body Fat Calculator: Estimate your body fat percentage.
- Another Health Tool: Explore other health and fitness calculators.